[Lustre-discuss] Dedicated MGS?

[Nathan Rutman]

Jakob Goldbach wrote:
>>> 1. If we are going to have several Lustre file systems, is there any
>>> reason not to create each one with its own combined MGS/MDT?
>>>       
>> Not that I'm aware of, with the restriction that you can only have a
>> single MGS running on a node at a time.  If you have failover MDSes,
>> then they need to share an MGS.
>>
>>     
>
> May a client mount different lustre-filsystems from different MGS's ?
>
> The manual (sec 2.1.1) says "There should be one MGS per site, not one MGS
> per file system."
>
> I thought this meant a single MGS if a client want's to mount several
> lustre-filesystems.
>   
It's not a requirement.  The idea behind a single MGS per site is that 
way, you can mount
multiple different Lustre FS's without having to keep track of which 
servers they are on
-- all you need to remember is the one mgsnid in "mount -t lustre 
mgsnid:/any_fs"
The idea is one centralized place for config data / starting clients / 
monitoring (eventually).

There will be one MGC on the client for each different MGS, so there's 
slightly more resource
usage if you do multiple MGS's, but no big deal.